Rivet set cooling device



Sept. 8,1936.

G.M.NELL' RIVET SET COOLING DEVICE Filed July 21, 1954 I lNyENTGR i filsmv' NEAL,

Patented Sept. 8, 1936 PATENT OFFICE RIVET SET COOLING DEVICE Gustave M.Nell, Detroit, cago Pneumatic Tool N. Y., a corporation of Mich.,as'signor to Chi- I Company, New York, New Jersey Application July21,1934, Serial No. 736,321

6 Claims. (o1. 1 21 s1) This invention relates to pneumatichammers, moreparticularly those hammers used for riveting wherein, owing to the heatfrom the rivets, the working tool, such as the rivet set and itsretaining clip, as well as the front end of the cylinder, becomeconsiderably heated, sometimes to an extent requiring the temporarydiscontinuance of the use of the hammer. In the riveting hammer art, itis well known that breakage at the shoulder joining the rivet set bodyto the shank is caused by conduction of heat from the rivet to the set,drawing its temper and tea large extent destroying the fatigueresistance of the heat-treated steel.

One object of the. invention is to provide means for cooling the workingtool, such as a rivet set, its retainer, or clip, and the front end ofthe hammer cylinder. Speaking in general terms, this result isaccomplished by so conducting the exhaust of the hammer that the samewill be discharged through passages extending to the front end of thecylinder andexhausted between the clip, or retainer,- and the workingtool or rivet set. 1

Another object of this invention is to prevent breakage at the end of acylinder having air passages for cooling a rivet set. In previousdevices of this type longitudinal bores provided in the cylinder Wallfor cooling purposes have resulted in longitudinal fatigue cracks whichsplit the cylinder, due to the excessive striking and clatter of therivet set shoulder against the end of the cylinder. In accordance withthe present invention breakage of the cylinder on its working end isprevented by arranging the cooling passages for a portion of theirlength between the inside surface of the. cylinder and the'outsidesurface of a bushing mounted therein. This bushing absorbs. a large partof the reaction blow trans- 'mitted from the set to the cylinder andmakes it possible to extend the cooling passages direct to the setshoulder without causing cracks at the surface adjacent to the passagesand engaged by the rivet set shoulder.

In the drawing:

Fig. 1 is a section of a portion of a hammer embodying the presentinvention;

Fig. 2 is a section on the line 2-2 of Fig. 1 showing the rivet set andretaining clip:

Fig. 3 is a section on the line 33 of Fig. 1;

Fig. 4 is a longitudinal section of the bushing; and

Fig. 5 is a perspective of the rivet set clip.

The illustrative embodiment comprises as its main parts the cylinder l0,piston ll adapted to reciprocate in the piston chamber l2, the work ingtool which is here a rivet set M, the tool retainer or rivet set clipl5, and the bushing I6.

The piston chamber I2 is provided with ports and passages controlled bya valve (not shown) and by the piston H for admitting and exhaustingpressure fluid, such as compressed air, from opposite sides of thepiston for causing the recip rocations of the latter. A supply passage,or bore I8, is formed in the wall of the cylinder ID. The 10 rear end ofbore I8 is connected to any suitable means for admitting pressure fluidthereto preferably, though not necessarily, the air exhausted from thecylinder. For a disclosure of a fluid pressure motor having means fordiverting a portion of the exhaust air through a cooling passage,reference is made to Stevens Patent 1,615,890 issued February 1, 1927.The front end of the cylinder It is provided with a counterbore 20communicating with the front end of supply passage l8. A bushing 24 isreceived by the cylinder counterbore 28 and secured to the cylinder byany suitable means, such as a pressfit. The rear end of bushing 2| restsagainst a shoulder 22 within the cylinder, the inside diameter'of whichis suf- 25 ficiently large to facilitate removal of the bushing by meansof a hook. The rear end of the bushing is also provided with aperipheral annular recess 24 adapted to register with the port at thefront end of the supply bore I8 and to form an 30 annular chamberbetween the bushing and cylinder supplied with air from said bore. Aplurality of longitudinal recesses 25 extend along the sur-' face of thebushing from the annular recess 24 to the frontend. The longitudinalrecesses a series of passages between the cylinder and bushing forconducting the cooling air from the annular chamber 24 to the shoulderon the rivet set. The working toolor rivet set body 21, a shank 28, anda shoul ing the shank to the body. serted into the bushing 2| a soconstructed and arranged the front end of both the bushing and cylinder.45 The rivet set is held in working relationship with the cylinder bymeans of the clip I5 which, as usual, is connected with the cylinder andalso operatively connected with the set. These clips are of temperedsheet metal and it is desirable that 50 they shall not be overheated.Therefore, in order to keep them as cool as possible, the exhaust orcooling passages 25 are arranged to discharge the exhaust air directlyagainst the shoulder of the set from whence such exhaust air isdeflected and 55 I4 comprises a 40 der 29 connect- The shank is innd theshoulder is that it may engage provide 35 passes between the set bodyand the clip as indicated by the arrows in Figs. 1 and 2.

In operation, the reciprocations of the piston and the reaction of thework against the rivet set I4 cause the latter to reciprocate through alimited distance to open and close the space between the shoulder 29 andthe end of the cylinder and bushing. Movement of the shoulder away fromthe cylinder end opens this space to admit exhaust air which impingesdirectly upon the shoulder thereby preventing overheating at the pointwhere breakage of the set is most likely to occur. Movement of airthrough the recesses or passages 25 cools the cylinder withoutnecessitating the employment of passages or openings which weaken thecylinder.

What I claim is:

1. In a riveting machine, a one-piece cylinder having an open endedbore, a bushing mounted in said bore and held therein by a press fit, arivet set received within said bushing, a retaining clip for the setconnected to the outside of the cylinder, means for delivering airbetween the set and clip for cooling said set and clip, said meanscomprising one or more passages in communication with both the cylinderand bushing for cooling both cylinder and bushing at the same time, saidpassage or passages being formed by a groove or grooves in the exteriorsurface of the bushing, which surface fits within a smooth unbrokencylindrical surface on the interior of the cylinder.

2. A riveting machine comprising a one-piece cylinder member having abore adapted to provide a piston chamber and having a counterbore at thefront end of the cylinder, a bushing received within said counterboreand held rigidly therein, a rivet set having a shank supported withinsaid bushing and having a shoulder adjacent the front end of thecylinder, said cylinder having a passage therein extendinglongitudinally thereof and opening into the rearward end of thecounterbore, the rear end of the bushing having an annular recess at itsperiphery adapted to form an annular chamber between the bushing andcylinder, said annular chamber being supplied with air under pressurefrom the longitudinal passage, of passages for conveying air from saidannular chamber and discharging the same at the front end of thecylinder, said last-named passages being formed by longitudinal groovesin the bushing and extending from the annular recess to the front end ofthe bushing and being positioned to discharge air against the rivet set,the interior of the cylinder having a smooth unbroken cylindricalsurface throughout substantially the entire length of the counterbore.

3. A riveting machine comprising a cylinder member having a bore at itsfront end, a bushing supported within said bore, a rivet set having ashank received within the bushing, said cylinder member having alongitudinal fluid carrying pasa series sage terminating short of thefront end of the cylinder, said bushing having an annular recessproviding an annular chamber between the bushing and cylinder, saidannular chamber being in communication with the longitudinal passage,the bushing having external longitudinal grooves arranged to coact withthe bore to form fluid carrying passages terminating at the front end ofthe cylinder member and discharging against the rivet set, said bushinghaving a press fit with the cylinder member throughout substantially theentire length of the bushing.

4. A riveting machine comprising a cylinder having a bore to provide apiston chamber and having a counterbore at the front end of thecylinder, a bushing mounted in the counterbore and seated against therear end of the counterbore with a press fit, a rivet set having a shanksupported within said bushing and adapted to receive impacts from apiston in said piston chamber, said rivet set having an integralshoulder adjacent the extreme front end of the cylinder and adapted toclatter against the front end of the cylinder during the operation ofthe machine, a rivet set clip carried by the front end of the cylinderand adapted to be engaged by the shoulder to prevent removal of therivet set from the cylinder, and means for cooling the front end of thecylinder, the bushing, the rivet set and the clip, said cooling meanscomprising a passageway in the wall of the cylinder communicating withthe interior of the counterbore at a point considerably remote from theextreme front end of the cylinder, one or more longitudinal grooves onthe external surface of the bushing, said grooves being positioned toreceive pressure fluid from the cylinder passageway and conduct saidfluid to the front end of the bushing and discharge said fluid againstthe shoulder of the rivet, the wall of the cylinder being imperforatenear the front end thereof, and the interior of the cylinder near thefront end thereof being defined by a smooth cylindrical surface, part ofwhich surface communicates with the groove or grooves, and the remainderof which surface is tightly engaged by the bushing.

5. A riveting machine according to claim 4 in which the cylinderpassageway terminates at a port adjacent the rear end of thecounterbore, and the longitudinal grooves in the bushing extendforwardly from said port throughout the entire length of the bushing.

6. A riveting machine according to claim 4 in which the bushing has anannular groove connecting the grooves in the bushing at the rearward endthereof, said annular groove being supplied with pressure fiui-d by thecylinder passageway.

GUSTAVE M. NEIL.

